This research aims to address the unexplained fact that hypertension is twice as common and more severe in black than white Americans, and that the racial difference is greatest in women. Investigations of many factors related to socioeconomic status (SES) (income, occupation, education, obesity) and to a possible genetic basis have failed, thus far, to account for the difference. The main problem is greater prevalence of hypertension in Blacks. Therefore, whatever pathways translate being Black in America into being hypertensive operate with increased frequency in Blacks but may not be fundamentally different from pathways to hypertension in Whites. To address the question of prevalence, the study population should include subjects who probably won't become hypertensive as well as those who will. We will study women 50 years old (premenopausal) with diastolic Bp 80 - 100 mm Hg. The sujbects will be Blacks and Whites at two occupational levels within the nursing profession, each level being relatively homogeneous with respect to major SES factors. Their BP reactivity to physical and psychophysiological stress in the laboratory and to the natural stress of a day at work (24-hour BP monitor) will be measured. Other measurements will include stress related changes in plasma catecholamines, renin, and aldosterone, and background dietary intake of salt, potassium, and calcium. The results should help answer the important question, is everyday psychophysiological hyperreactivity a significantly more frequent pathway to hypertension in Black than White American women?